Detection of biomarkers with graphene nanoplatelets and nanoribbons

Well-defined graphene nanosheets have become increasingly popular in the electrochemical detection and quantification of small molecules. In this work, the electrochemical oxidation of biomarkers such as uric acid, ascorbic acid, dopamine, NADH and DNA bases, namely guanine and adenine, was performed using cyclic voltammetry and differential pulse voltammetry to compare the electrochemical properties of electrochemically reduced nanoplatelets (ENPs) and electrochemically reduced nanoribbons (ENRs). The graphene materials displayed better electrochemical performances than the bare glassy carbon surface. Between the two graphene materials, the oxidation of biomarkers occurred at lower oxidation potentials on the ENP surface. The sensitivities of the two graphene surfaces varied when different biomarkers were studied. The ENP surface showed enhanced sensitivities for ascorbic acid, while the ENR surface exhibited higher sensitivities for uric acid and dopamine. As for the DNA bases analysed, both guanine and adenine were oxidised at lower potentials on the ENP surface than the ENR surface. The ENP surface displayed a better sensitivity for guanine, whereas the oxidation of adenine was more sensitive on the ENR surface.